[Correction] Engine Fuel & Control – Hydromechanical Metering Unit – Replacement
- Published
- Effective
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must replace affected HMUs on ARRIUS 1A engines within specified compliance times based on engine cycles, with some replacements required before the next flight. For helicopters with two affected engines, at least one HMU must be replaced promptly, followed by the second as per the directive's schedule. Installation of affected HMUs is prohibited from the effective date, and a single ferry flight without passengers is permitted to reach a maintenance facility if necessary.
Summary
EASA Airworthiness Directive 2026-0128 is a corrective directive addressing the replacement of Hydromechanical Metering Units (HMUs) on SAFRAN Helicopter Engines ARRIUS 1A models, commonly installed on Airbus Helicopters AS 355 N twin-engine helicopters. The directive targets specific HMUs with part number 0164851170 identified as having a torn constant delta P valve diaphragm, which could cause fuel flow drift and potential engine shutdown. It mandates replacement of affected HMUs to ensure continued airworthiness and safe engine operation.
What changed
This directive corrects a previously issued AD by updating the part number reference for the affected HMUs. It introduces mandatory replacement requirements for the identified faulty HMUs and prohibits their installation on any engine from the effective date. Additionally, it specifies compliance times based on engine usage cycles and allows a single ferry flight under certain conditions to facilitate maintenance.
Why it matters
This AD is critical for aviation professionals as it addresses a safety risk that could lead to uncommanded engine shutdowns, significantly impacting helicopter control and flight safety. Operators and maintenance organizations must ensure timely compliance to avoid operational disruptions and regulatory non-compliance. The directive also clarifies installation restrictions and provides guidance on managing affected components to maintain airworthiness.
More for Safran ARRIUS 1
All 4- EASA AD 2024-0148Time Limits / Maintenance Checks — Airworthiness Limitations Section — AmendmentJul 30, 2024
- EASA AD 2022-0005Time Limits / Maintenance Checks — Airworthiness Limitations Section — AmendmentJan 11, 2022
- EASA AD 2019-0266-EEngine — Module 02 / Gas Generator — Service Life Calculation / ReplacementOct 25, 2019
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